1. Field of the Invention
The present invention relates to a gallium nitride (GaN) compound semiconductor light emitting element capable of emitting light in the range of the blue region to the ultraviolet region.
2. Description of the Related Art
When a current blocking type or ridge waveguide type compound semiconductor laser is fabricated, a process of etching compound semiconductor layers of the laser to respective specified thicknesses with high precision or a process of selectively etching a layer to expose the surface of an underlying layer is required.
In the etching of a GaAs compound semiconductor layer, wet etching with high selectivity is normally employed. In the etching of a GaN compound semiconductor, dry etching is normally employed since no appropriate etchant is available. By dry etching, however, etching of a GaN compound semiconductor layer with sufficient selectivity is difficult. A GaN compound semiconductor which cannot be etched with sufficient selectivity will not be usable as a dry etching stop layer. Therefore, it is difficult to fabricate a current blocking type or ridge waveguide type semiconductor layer by dry etching with good reproducibility.
J. Vac. Sci. Technol., A 11 (4) 1993 pp. 1772-1775 describes the etching of GaN, InN, and AlN by ECR-RIBE (electron cyclotron resonance type reactive ion beam etching) which is one of the dry etching methods. This article discusses that the etching rate in this method has selectivity.